1. Field of the Invention
The invention relates to a heat-dissipating apparatus for an integrated circuit device, more particularly to a heat-dissipating apparatus that is simple to manufacture and assemble and that prevents condensation of water droplets therein.
2. Description of the Related Art
Electronic devices, such as integrated circuit devices, generate heat during operation. The heat or rise in temperature will affect the dynamic characteristics of an electronic device and hence shorten the service life thereof. A heat-dissipating apparatus can help dissipate the heat of the electronic device to thereby prolong the service life and increase the operational speed thereof.
A conventional heat-dissipating apparatus is shown in FIG. 1. As illustrated, the heat-dissipating apparatus includes a cooling fin member 1 and a fan 2 mounted on top of the cooling fin member 1. During operation, the heat generated by an integrated circuit device is transferred to the cooling fin member 1, and the fan 2 generates a current of air to dissipate the heat transferred to the cooling fin member 1. However, as air is not a good heat conductor, the heat-dissipating effect of the fan 2 is not satisfactory. Besides, in order not to obstruct the discharge of hot air by the fan 2, the fan 2 and hence the integrated circuit device cannot be disposed too close to a wall surface, thereby affecting the utility of the apparatus.
FIG. 2 shows another conventional heat-dissipating apparatus. As illustrated, a thermoelectric cooling unit 5 is disposed between an integrated circuit device 3 and a fan 4. The fan 4 and the cooling unit 5 are secured on a circuit board 7 by using a mounting bracket 6. The cooling unit 5 is a semiconductor device that includes an array of N-type semiconductor units 501, P-type semiconductor units 502, and metal conductors 503 interconnecting the N-type and P-type semiconductor units 501, 502. First and second ceramic sheets 504, 505 are respectively disposed on upper and lower sides of the array. The first ceramic sheet 505 has a top side forming a heat-releasing side, while the second ceramic sheet 505 has a bottom side in contact with the integrated circuit device 3 and forming a heat-absorbing side. When an electric current is passed through the metal conductors 503, electrons move from the negative pole and through the P-type semiconductor units 502, where heat is absorbed, and to the adjacent N-type semiconductor units 501, where heat is released. At each passage of the electrons through one NP module, there is a transfer of heat from one side to the other, thereby creating a temperature difference at the heat-absorbing and heat-releasing sides. The arrangement of the cooling unit 5 can thus transfer the heat generated by the integrated circuit device 3 via the ceramic sheet 505 at the heat-absorbing side to the ceramic sheet 504 at the heat-releasing side so as to be dissipated to the outside through the use of the fan 4.
Although the heat-dissipating apparatus of FIG. 2 provides a better heat-dissipating effect over that of FIG. 1, since the integrated circuit device 3 is only in contact with the central portion of the heat-absorbing side, condensation of water droplets may occur at the remaining portion of the heat-absorbing side, where the temperature is likewise relatively low, when exposed to the ambient air. The water droplets may drip to the circuit board 7 therebelow, thereby resulting in short-circuit and shortened service life for the circuit board 7. Moreover, the dissipation of heat by using air currents generated by the fan 4 is also inefficient since air is not a good heat conductor.